Early Research – Lawrence Pinneo

The work of Lawrence Pinneo in the early seventies often comes up in mind control discussions. It is cited as evidence that a thought reading capability has been around for some time. A report by Pinneo is available at the “Christians Against Mental Slavery” website, so I decided to download it and take a look at what it was all about.

The report, “Feasibility Study for Design of a Biocybernetic Communication System”, written in 1975 details the findings of a three year study sponsored by DARPA and conducted by a team from SRI (Stanford Research Institute) lead by Pinneo, a neurophysiologist and electronic engineer. The work was part of a larger DARPA Biocybernetics Program whose directive was to evaluate the potential of biological measurable signals helped by real-time computer processing, to assist in the control of vehicles, weaponry, or other systems.

The work is remarkable for the time given the computing power available. The computers used were a CDC 6400 a machine and a LINC-8, machines which were typically loaded using punched cards and paper tape. The laptop I’m writing this blog on is probably on the order of many thousand times more powerful than these machines.

The stated goal of the research was

… to test the feasibility of designing a close-coupled, two-way communication link between man and computer using biological information from muscles of the vocal apparatus and the electrical activity of the brain during overt and covert (verbal thinking) speech. The research plan was predicated on existing evidence that verbal ideas or thoughts are subvocally represented in the muscles of the vocal apparatus.

Covert speech is more commonly called subvocal speech today and refers to verbal thinking where you think to yourself in words. At the time it was known that even though no sounds are generated during this covert speech electrical signals are still sent to the muscles of the face and throat which can be detected using electromyography similar to an electroencephalography. So the goal was essentially to investigate electrical signals from the brain (EEG) and muscle nerves (EMG) during covert and overt speech and to determine what information could be extracted from them.

Electrodes were placed on both the head and facial musculature to capture EEG and EMG readings. See the original document for exact placement. Subjects were placed in a shielded booth where words were presented on a screen and they had to either say(overtly) or think (covertly) the word they saw. The signals from the electrodes were captured and fed through an analog to digital converter and into the computer.

The processing of the signals was fairly straightforward. For the study he worked with a set of 15 words.For each word the signal amplitude was sampled over a 6 second period – three seconds before to three seconds after the word is uttered or thought. 255 samples were taken in total. For each word he constructed a template, basically all 255 sample points averaged over ten repetitions of the word.

When it came to predicting which word a subject was thinking of he would simply compare the measured sample to each of the 15 templates and calculate the root mean square(RMS) of each templates difference from the measured value. The word whose template had the lowest RMS value was chosen as the word the subject was deemed to be thinking.

This type of processing was repeated for a number of subjects for both overt and covert speech. A wide range of experimental factors was also tested such as electrode placement, male versus female, etc.

The report has a number of findings, here are some of the highlights

EEG responses for covert speech mimicked those of overt speech for the same subject, electrode, and spoken word. When sources of error were reduced as much as possible, correct computer classification rates ranged from 52 to 72%,

EMG values performed better than EMG/EEG combined which performed better than EEG alone

When templates of one subject were used to classify words based on individual responses of another subject, the percentage of correct classifications for EEG responses was no greater than chance expectation. The percentageof correct classifications for EMG was greater than chance, but not nearly so good as within subjects. Thus, each subject’s biological patterns associated with speech appear to be unique

Performance would be better if known sources of error were removed such as time and amplitude variations and muscle and eye movement artifacts.

Stored patterns should be “refreshed” periodically (i.e., new templates should be formed and updated) to take ac­count of “drifting” cortical organization

The system performed best for subjects who have strong hemispheric lateralization for language.

In the end Pinneo concluded that

…it is feasible to use the human EEG coincident with overt and covert speech as inputs to a com­puter for such communication. However, we also conclude that, without additional research, the EEG is not adequate for the design of a prac­tical operating system; indeed, other methods than those employed here may prove superior. Nevertheless, enough information has been obtained during this proj­ect to specify the optimum parameters to use for an EEG-operating system and to suggest future research toward that end. Our results show con­clusively that consistent, repeatable patterns exist in the EEG during overt speech (for example, see Figure 19) and covert speech (Figures 13 and 14) and that a computer can recognize these patterns a statistically significant percentage of the time.

Pinneo does not worry that mind-reading computers might be abused by Big Brotherly governments or overly zealous police trying to ferret out the innermost thoughts of citizens. Rather than a menace, he says, they could be a highly civilizing influence. In the future, Pinneo speculates, technology may well be sufficiently advanced to feed information from the computer directly back into the brain. People with problems, for example, might don mind-reading helmets (“thinking caps”) that let the computer help them untangle everything from complex tax returns to matrimonial messes.

This was definitely groundbreaking work and there is no doubt that it grabbed the attention of people within the defense and intelligence communities. In the non-classified world this work has been taken up Chuck Jorgensen of NASA who I’ll come back to in a future post.